Thermal production process for oil wells and method of equipping such wells



July 4, 1967 J. R. BROWN THERMAL PRODUCTION PROCESS FOR OIL WELLS AND METHOD OF EQUIPPING SUCH WELLS Filed July 2, 1965 A? ll HEA TING 3 Janasrmwm INVENTOR.

United States Patent Ofiice 3,329,205 THERMAL PRODUCTION PROCESS FOR OIL WELLS AND METHOD OF EQUIPPIN G SUCH .WELLS Joe R. Brown, 5649 Tupper Lake, Houston, Tex. 77027 Filed July 2, 1965, Ser. No. 469,151 6 Claims. (Cl. 16619) This invention relates to a thermal production process for oil wells, and more particularly to a method for equipping wells for the recovery of oil by the employment of a vaporous heating medium.

In certain petroleum-containing earth formations, the petroleum is in the form of highly viscous hydrocarbons which will not flow freely from the formation. Such petroleum cannot be produced by ordinary original or secondary recovery methods and processes are now being developed for heating the subsurface formations to liquefy the oil sufficiently so that it can be caused to flow naturally, or be produced by gas or water pressures.

One thermal production process now being developed and employed involves the use of steam or heated gas as the medium which must be injected into the formation containing the viscous petroleum to effect the desired degree of liquefaction of petroleum.

While such methods are proving successful in many instances, a number of problems occur, particularly in connection with preparing the well bore for receiving and properly directing the heating fluid to the formations to be treated there-by.

This invention has for its primary object the provision of an improved thermal production method.

An important object is the provision of a method by which a well bore may be suitably conditioned and equipped for eifective injection of heating fluid to earth formations.

A further object is the provision of a steam injection method for producing oil wells.

The procedure in accordance with this invention for equipping the well, contemplates the steps of inserting into the well bore a string of tools comprising a screen liner and a gravel packing assembly detachably secured to the upper end of the liner, positioning the liner opposite the prospective producing formation, directing gravel-carrying fluid downwardly into the annulus between the liner and well bore wall from a point above the formation to form in the annulus a gravel pack between the face of the formation and the liner, thereafter detaching the gravel packing assembly from the liner and withdrawing it from the well bore, replacing the gravel packing assembly by an expansible packer carried on a pipe string into the well bore and connecting the packer to the upper end of the liner in order to communicate the pipe string with the interior of the liner, and finally injecting heated fluid, such as steam, through the pipe string, the liner, and gravel pack into the formation to render flowable any normally non-flowable hydrocarbons contained in the formation.

Other and more specific objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a useful embodiment in accordance with this invention.

In the drawing:

FIGS. 1, 2 and 3 are similar partly sectional, partly diagrammatic illustrations of several stages in the procedure for equipping a well for thermal productions.

Referring to the drawing and to FIG. 1, wherein the first stage of operation in equipping a well is illustrated, there is shown a well bore W intersecting an earth formation P which contains the petroleum which is not flowable under the natural conditions existing in the formation. At

3,329,205" Patented July 4, 1967 a point above formation F, the well is lined in the usual manner by a metal casing C which has been cemented in place in accordance with conventional practice. The first stage in equipping a well comprises the insertion into the well bore of a string of tools which are run on operating pipe string P. The string of tools comprises a liner L having a series of screen slots 1 and connected at its lower end to a valved shoe 2 having openings 3 therein and provided with a check valve 4 by which fluid may flow downwardly from the line through the shoe, but will prevent backward flow from the shoe to the liner. The liner is also provided with a plurality of circulation slots 5 positioned above screen slots 1, for purposes which will appear subsequently. A sleeve valve 6 is slidably disposed in the line L above the circulation slots and is initially held in position above the slots by means of shear pins 7.

A gravel packing assembly A of the reverse placement type, such as is disclosed in my US. Patent No. 3,072,204,

is connected at one end to operating pipe P and detachably connected at the other end to the upper end of liner L.

While the details of the gravel packing assembly do not form a part of the present invention, the structure will be described in some detail for purposes of illustration of the procedure employed in the present invention.

Assembly A includes a tubular body 10 which is thread ably connected by a collar 11 to operating pipe P. The lower end of body 10 is reduced in diameter to form a downwardly facing shoulder 12 adapted to seat on the upper end of line L. An elongate tubular mandrel 13 is secured to the lower end of body 10 to extend axially into the bore of liner L to a point below screen slots 1. A nut 14 is threadedly connected to liner L and is secured by longitudinal splines 15 to mandrel 13, the arrangement being such that when the assembly is rotated relative to liner L, nut .14 will be unscrewed from liner 4 to release the gravel packing assembly from the connection to the liner and allow it to be withdrawn, as will appear subsequently. Mandrel 13 is provided with an external enlargement 16 carrying an annular seal 17 for sealing oif between the mandrel and liner L below nut 14. The gravel packing assembly also includes an inner tubular body 18 radially spaced from body 10 and extending into the bore of mandrel 13. A plurality of laterally disposed nipples 19 communicates the bore of inner body 18 with the exterior of body 10, whereby fluid flowing downwardly through pipe P may be directed into the annulus U between the tool string and the wall of well W. The annular space between outer body 10 and inner body 18 provided the bypass passage 20 which by-passes nipples 19, and communicates with the bore of inner body 18 through ports 21 at points below nipples 19. Outer body 10 is provided with ports 22 communicating by-pass passage 20 with the annulus between casing C and pipe P. A cup-shaped seal member 23 is mounted about outer body 10 at a point between the outlets of nipples 19 and ports 22 to seal ofi the annulus between outer body 10 and casing C at said point. Inner body 18 is provided at its upper end with a seat 24 for reception of a plug 25 adapted to close the bore of body 18 at a point between nipples 19 and ports 21.

The lower end of mandrel 13 is slidably received in the bore of a closure ring 26 provided in the bore of liner L below screen slots 1. A seal packing 27 is disposed between ring 26 and the exterior of the mandrel to seal off between these elements. The lower portion of mandrel 13 is provided with lower circulation ports 28 at a point above packing 27 and generally opposite screen slots 1. A sleeve valve 29 of the velocity-actuated type is mounted about the mandrel in position normally closing ports 28 but is adapted, in response to velocity of fluid flowing through the screen slots, to be moved upwardly into a position opening ports 28 for passage of such fluid into the bore of mandrel 13 (FIG. 1). Mounted above valve 29 on the exterior of mandrel 13 is a set of dogs 30 which are biased to swing outwardly when the mandrel has been drawn upwardly in the liner past an internal shoulder 31 in the liner. These dogs are adapted, when the mandrel has been elevated sufliciently, to extend over the upper end of sleeve valve 6 and may be employed as a hammer operable by downward movement of the mandrel to break shear pins 7 and drive sleeve valve 6 downwardly to a position closing circulation slots 5, as seen in FIG. 2, for purposes to be described subsequently.

The first stage operation is conducted in the following manner: The string of tools just described, carried on operating pipe P, will be run into the well from the surface until the portion of the screen liner containing screen slots 1 will be opposite the face of formation F. Thereupon, plug 25 will be dropped through the bore of the operating pipe and pumped down by means of fluid being introduced into the pipe string until it seats on shoulder 24, thereby closing off the bore of inner body 18 and mandrel 13 at a point just below the nipples 19. Fluid carrying the fine gravel conventionally used for gravel packing wells, will then be pumped down the operating pipe P and will flow, as indicated by the arrows in FIG. 1, outwardly through nipples 19 into annulus U between the tool string and the wall of well W. The grave-carrying fluid will then flow downwardly, dropping its gravel into the lower portion of the annulus, beginning with the bottom of the well, and will gradually accumulate in an upward direction to any predetermined depth above formation F. As the gravelcarrying fluid flows down the annulus, the gravel will, as will be evident, be screened out from the fluid by the slots 1 and the gravel-free liquid will then flow through slots 1 and circulation slots 5. The fluid entering the liner will move velocity valve 29 upwardly, opening ports 28, and permitting the gravel-free fluid to flow upwardly through the bore of mandrel 13 and inner body 18, from which the fluid will pass through ports 21, by-pass passage 20 and out upper circuation ports 22 above seal member 23. The fluid will thus enter the annulus between pipe string P and casing C and return to the surface.

When a gravel pack of sufficient depth has thus been introduced between the liner and formation F, the gravel packing assembly will be disconnected from the upper end of the liner and withdrawn from the well. As indicated previously, release and removal of the gravel packing assembly will be effected by rotating pipe string P to which the gravel packing assembly is connected. This rotation will cause nut 14 to be unscrewed from the liner, travelling upward along splines 15 to effect such release. When the nut has been released, the operating string will be drawn upwardly, raising the gravel packing assembly A upwardly out of its connection with the liner, as shown in FIG. 2. When mandrel 13 has moved upwardly to an elevation sufficient to place dogs 30 above the upper end of sleeve valve 6, the operating string may be lowered so as to cause the dogs to engage the upper end of the sleeve valve, whereupon the application of downward weight or jarring action transmitted through the operating string may be employed to break shear pins 7 and drive the sleeve valve down to a position closing circulation ports 5. When this has been accomplished, the operating string, carrying the gravel packing assembly, will be withdrawn from the well.

In the next stage of operations, an expansible seal packer K will be connected to production pipe string P and run back into the well bore for connection to the upper end of liner L. The details of packer K do not form a part of the present invention, as this packer may be of any suitable and generally known design. As illustrated, the packer includes a coupling sleeve 35 connected to the lower end thereof, having an annular recess 36 therein opening downwardly for receiving the upper end of liner L. Seal packing 37 is provided in the bottom of recess 36 to provide a fluid-tight seal between coupling 35 and the upper end of liner L. Coupling 35 may be provided with sloping guide flanges 33 to guide the coupling over the end of liner L when the packer is run into the Well. Packer K is provided with the usual anchor and seal assembly including pipe gripping slips 41, a resilient expansible seal member 40 and with relatively movable compression elements 42 by which seal member 40 may be axially compressed and thereby radially expanded to seal off the annulus between the packer body and casing C. The bore of the packer will place production pipe P into communication with the bore of liner L. Setting of the packer will be eifected in the known manner by rotation of pipe string P driving compression elements 42 in a direction to compress seal member 40.

When the packer has been set, as described, a suitable vaporous thermal fluid, such as steam or hot gas, indicated by the arrows in FIG. 3, may be directed through operating pipe P and conducted through the bore of the packer and liner L to screen slots 1 through which the heated fluid will discharge through the gravel pack G, and thence into formation F, where it will heat the hydrocarbons present in the formation sufiicienty to render them flowable, after which the natural pressure conditions in the formation will usually cause the liquefied material to flow into the liner and thence to the surface after the heating has been terminated.

It will be understood the procedures herein described are illustrative only and do not limit the. scope of the invention as defined by the appended claims.

What I claim and desire to secure by Letters Patent is:

1. The method of equipping a well for thermal production of oil therefrom, comprising, inserting into a well bore a string of tools comprising a screen liner and a gravel packing assembly detachably secured to the upper end of said liner, positioning the liner opposite a prospective producing formation, directing gravel through said assembly downwardly into the annulus between said liner and the well bore wall to form in said annulus a gravel pack of predetermined depth opposite said formation, thereafter detaching said gravel packing assembly from the liner and withdrawing the assembly from the well bore, carrying an expansible packer into the well bore on a pipe string and connecting the packer to the upper end of the liner to communicate the pipe string with the interior of the liner, and expanding the packer to seal off the annulus between the pipe string and the well bore wall above said gravel pack.

2. The method of equipping a well for thermal production of oil therefrom, comprising, inserting into a well bore a string of tools comprising a screen liner and a gravel packing assembly detachably secured to the upper end of said liner, positioning the liner opposite a prospective producing formation, directing a gravel-carrying fluid through said assembly downwardly into the annulus between said liner and the well bore wall, screening out the gravel from the fluid to form in said annulus a gravel pack accumulated upwardly therein to a predetermined depth opposite said formation, returning the gravel-free fluid to the surface through the well annulus above said assembly, thereafter detaching said gravel packing assembly from the liner and withdrawing the assembly from the well bore, carrying an expansible packer into the well bore on a pipe string and connecting the packer to the upper end of the liner to communicate the pipe string with the interior of the liner, and expanding the packer to seal off the annulus between the pipe string and the well bore wall above said gravel pack.

3. A thermal production process for wells, comprising inserting into a well bore a string of tools comprising a screen liner and a gravel packing assembly detachably secured to the upper end of said liner, positioning the liner opposite a prospective producing formation, directing gravel through said assembly downwardly into the annulus between said liner and the well bore wall to form in said annulus a gravel pack of predetermined depth opposite said formation, thereafter detaching said gravel packing assembly from the liner and withdrawing the assembly from the Well bore, carrying an expansible packer into the well bore on a pipe string and connecting the packer to the upper end of the liner to communicate the pipe string with the interior of the liner, expanding the packer to seal off the annulus between the pipe string and the well bore wall above said gravel pack, and injecting a heated vaporous fluid through said pipe string, liner and gravel pack into said formation to render flowable any normally nonflowable hydrocarbons contained in said formation.

4. The process according to claim 3 wherein said heated vaporous fluid is steam.

5. A thermal production process for wells, comprising, inserting into a Well bore a string of tools comprising a screen liner and a gravel packing assembly detachably secured to the upper end of said liner, positioning the liner opposite a prospective producing formation, directing a gravel-carrying fluid through said assembly downwardly into the annulus between said liner and the Well bore wall, screening out the gravel from the fluid to form in said annulus a gravel pack accumulated upwardly therein to a predetermined depth opposite said formation, returning the gravel-free fluid to the surface through the well annulus above said assembly, thereafter detaching said gravel packing assembly from the liner and withdrawing the assembly from the well bore, carrying an expansible packer into the well bore on a pipe string and connecting the packer to the'upper end of the liner to communicate the pipe string with the interior of the liner, expanding the packer to seal off the annulus between the pipe string and the well bore wall above said gravel pack, and injecting a heated vaporous fluid through said pipe string, liner and gravel pack into said formation to render flowable any normally non-flowable hydrocarbons contained in said formation.

6. The process according to claim 5 wherein said heated vaporous fluid is steam.

References Cited UNITED STATES PATENTS 2,207,334 7/1940 Reynolds 166-20 X 2,896,714 7/1959 Killingsworth 166-20 X 3,062,284 11/1962 Brown 16619 CHARLES E. OCONNELL, Primary Examiner.

N. C. BYERS, Assistant Examiner. 

5. A THERMAL PRODUCTION PROCESS FOR WELLS, COMPRISING, INSERTING INTO A WELL BORE A STRING OF TOOLS COMPRISNG A SCREEN LINER AND A GRAVEL PACKING ASSEMBLY DETACHABLY SECURED TO THE UPPER END OF SAID LINER, POSITIONING THE LINER OPPOSITE A PROSPECTIVE PRODUCING FORMATION, DIRECTING A GRAVEL-CARRYING FLUID THROUGH SAID ASSEMBLY DOWNWARDLY INTO THE ANNULUS BETWEEN SAID LINER AND THE WELL BORE WALL, SCREENING OUT THE GRAVEL FROM THE FLUID TO FORM IN SAID ANNULUS A GRAVEL PACK ACCUMULATED UPWARDLY THEREIN TO A PREDETERMINED DEPTH OPPOSITE SAID FORMATION, RETURNING THE GRAVEL-FREE FLUID TO THE SURFACE THROUGH THE WELL ANNULUS ABOVE SAID ASSEMBLY, THEREAFTER DETACHING SAID GRAVEL PACKING ASSEMBLY FROM THE LINER AND WITHDRAWING THE ASSEMBLY FROM THE WELL BORE, CARRYING AN EX- 